The present invention relates to a device for the magnetic treatment of water to reduce the buildup of scale.
A problem which is quite prevalent in systems and apparatus which use large amounts of water, such as boilers, dishwashers, ice machines, and the like, is that of scale buildup on the surfaces which come into contact with the water. This is especially troublesome in areas where the water has a high mineral content so that it is necessary for the water to be "conditioned" either by chemical action or by magnetic water treatment devices of the general type to which the present invention relates.
One such magnetic treatment device is disclosed in U.S. Pat. No. 3,951,807 to Charles H. Sanderson and comprises an elongated magnet having a multiplicity of longitudinally spaced poles encased in a non-magnetic jacket and concentrically positioned within a galvanized outer casing made of a magnetic material, such as iron. The jacketed magnet is centered by means of a pair of stepped collars secured thereto which, in turn, are centered by means of a pair of layered inserts.
Another magnetic water treatment device, which is commercially available, comprises an outer casing of magnetic material, an intermediate casing made of plastic, and an elongated permanent magnet encased within a plastic jacket having helical vanes which support the magnet centrally within the intermediate casing. Non-magnetic end caps are threadedly secured to opposite ends of the intermediate casing and O-rings are compressed between flanges on the end caps and the outer casing.
Magnetic treatment devices generally of this type are well known and prevent the buildup of scale by causing the calcium and other minerals present in hard water to form, instead, a loose slurry which can be removed easily from the system by blowdown or flushing. In many applications, such as furnace humidifiers, for example, it is necessary that the device be contained within a fairly small housing, and for this reason, available space is at a premium. The effectiveness with which the water is treated depends on the intensity of the magnetic field within the treating chamber and the effective length of the chamber itself. Accordingly, it is desirable that the chamber be free of any obstructions which may occupy otherwise available treatment space, and for the water to be directed into and completely occupy the annular treatment chamber as quickly and in as short a distance as possible after it enters the device.
A further consideration is that the strength of the magnetic field produced by the magnet be confined solely to the annular treatment chamber so that all of the available flux will be utilized. An important factor in ensuring this situation is to completely magnetically isolate the magnet from the supporting structure and to complete the magnetic circuit by means of a ferrous casing which surrounds the magnet, and which is also magnetically insulated from its supporting structure and from the magnet.
In the aforementioned patent application Ser. No. 798,854, the magnet structure is disclosed as centrally supported within the ferrous casing by means of a pair of non-magnetic, elastic sleeves compressed between and in frictional engagement with the magnet structure and the ferrous casing at opposite ends thereof. Additionally, the magnet is frictionally retained within its jacket by a pair of plastic end caps which further insulate the magnet and also serves to prevent water from coming into contact with it thereby causing corrosion.
Although the frictional engagement between the inner casing and plastic end caps and between the inner casing and the elastic sleeves serves to hold the structure in proper position in normal use, a severe jolt to the unit, as by dropping it during shipping or installation, may cause the magnet to shift axially thereby partially or completely blocking one set of the apertures. Obviously, this would prevent proper flow of water through the device. Furthermore, it is possible for the inner casing to shift relative to one of the elastic sleeves, and this also would result in partial or complete blocking of one set of the apertures. Axial shifting of the magnet relative to the inner casing may also be caused by a severe water hammer occurring in the water supply system in which the device is connected.